This invention relates to explosive sources for ejector systems, that forcefully release stores (bombs) from an aircraft.
In typical ejector systems the store is restrained by a pair of latches that hook into lugs attached to the store. The latches are operatively connected to an over-center release mechanism that is actuated when an explosive cartridge is detonated. The cartridge provides a pressurized gas to an unlocking piston which in turn moves the over-center linkage and releases the latches from the store. At the same time, the pressurized gas is manifolded into two ejection piston cylinders, wherein the pistons extend and forcefully eject the store from the aircraft. This type of system is disclosed in U.S. Pat. No. 4,050,656 by PETERSON, see also U.S. Pat. No. 4,347,777 by JAKUBOWSKI, et al, on over-center release mechanisms.
It is important that the ejector pistons thrust the store through the airstream envelope of the aircraft. Failure to extend the store beyond the airstream envelope could cause the store to deviate from its intended target, or to ride in the airstream and damage the aircraft. To insure store detachment, a set of design criteria have been established wherein the store must obtain a predetermined velocity when it is released from the ejector piston. For example, certain older aircraft required that a 500 lb. store be released at a velocity of 12 ft/sec. As aircraft become faster the velocity requirement becomes higher, with even higher velocities needed for bombers, where the store must exit from the fuselage of the aircraft.
At present, explosive cartridges come in standard units wherein each size of cartridge provides a predetermined amount of energy. To obtain a desired store velocity a corresponding number of cartridges are used in the system. Generally speaking, store velocity can be increased by adding cartridges to the system. The simultaneous detonation of the cartridges providing enough energy to eject the store at the required velocity. As the number of cartridges are increased, the force and corresponding shock exerted on the store also increases. Because modern stores, particularly guided bombs, have a large amount of electronics, the stores are sensitive to shock. It is therefore desirable to have an high energy ejector system that provides a smooth continuous force to the store.
One type of system that addresses this problem is disclosed in U.S. Pat. No. 4,850,553 by TAKATA, et al. The Takata system has a pair of telescoping pistons that provides a stepped reduction of piston area as the piston is extended, causing an increase in piston force. This system produces a more continuous piston force, but still has the initial shock spike caused by the simultaneous detonation of the explosive cartridges. In addition, the pistons lock upon extension, requiring the rack to be manually reset, a time consuming function. Therefore what is needed is an ejector system that provides a continuous ejector force, using standard explosive cartridge and telescoping ejector piston components.